CN115404298B - Coal injection method for European smelting furnace - Google Patents

Coal injection method for European smelting furnace Download PDF

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CN115404298B
CN115404298B CN202210969806.6A CN202210969806A CN115404298B CN 115404298 B CN115404298 B CN 115404298B CN 202210969806 A CN202210969806 A CN 202210969806A CN 115404298 B CN115404298 B CN 115404298B
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coal
furnace
ratio
oxygen
coke
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CN115404298A (en
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季书民
邹庆峰
贾志国
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Xinjiang Bayi Iron and Steel Co Ltd
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Xinjiang Bayi Iron and Steel Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B13/00Making spongy iron or liquid steel, by direct processes
    • C21B13/0066Preliminary conditioning of the solid carbonaceous reductant
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B13/00Making spongy iron or liquid steel, by direct processes
    • C21B13/0073Selection or treatment of the reducing gases
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B13/00Making spongy iron or liquid steel, by direct processes
    • C21B13/02Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • C21B13/023Making spongy iron or liquid steel, by direct processes in shaft furnaces wherein iron or steel is obtained in a molten state

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  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
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  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture Of Iron (AREA)

Abstract

The invention discloses a coal injection method of an European smelting furnace, which adopts a bituminous coal injection process to mix bituminous coal with the volatile content of more than 35 percent with low-volatile semi-coke according to the mass ratio of 3:1, so that the volatile content of the mixed fuel is slightly less than 25 percent, and the mixed fuel is crushed into crushed coal and then is filled into a raw coal bin; grinding crushed coal to minus 200 meshes which account for more than 60% by a coal mill to prepare coal powder; drying the pulverized coal by adopting flue gas generated by a flue gas furnace to enable the moisture of the pulverized coal to be less than 2%; the oxygen content of the coal grinding and pulverizing system is less than 12%, and the CO content is less than 300ppm; the flue gas enters a coal mill by means of the suction force of a smoke exhaust fan to convey pulverized coal to a cloth bag box body, and finished pulverized coal is loaded into a pulverized coal bin after gas-powder separation in the cloth bag box body; sequentially filling pulverized coal into 3 blowing tanks at the lower part of a cloth bag box body, and blowing pulverized coal to the vault of the gasification furnace of the European and Metallurgical furnace and an oxygen tuyere; the invention can improve the quality of the reduction gas of the European smelting furnace, reach the CO2 content of less than 9 percent in the reduction gas of the European smelting furnace, further optimize the fuel structure of the European smelting furnace and reduce the fuel ratio.

Description

Coal injection method for European smelting furnace
Technical Field
The invention relates to a coal injection method of a European smelting furnace.
Background
In order to solve the problems of large investment scale and large pollution in the traditional blast furnace iron-making method, a COREX furnace iron-making method, namely a smelting reduction iron-making method, is developed in the world from the seventies of the last century. The iron-smelting method directly uses lump coal and a small amount of low-strength coke to enter a furnace for generating heat for smelting molten iron and reducing coal gas.
At present, there are five sets of COREX devices being produced in the world:
1) The Korean Pu Chart factory (Pohang), first C2000COREX furnace, produced molten iron 60-80 ten thousand t/a, was put into production in 1995. The production of the plant is stable, the operation rate exceeds 95%, and the output gas of the COREX furnace is used for generating electricity.
2) In JINDAL plant, two C2000COREX furnaces, 2X 80 ten thousand t/a, were set up in 1999 in 12 months, and in 2001 in 8 months. And outputting the gas for generating electricity and producing pellets.
3) The south Africa SALDANHA factory, a C2000COREX furnace and a direct reduction shaft furnace, the COREX furnace produces 65 ten thousand t/a of molten iron, and the production is put into production in 12 months of 1998. The output gas of the COREX furnace is used for producing direct reduced iron by a direct reduction furnace. The COREX furnace used 80% of lump ore.
4) The eight-steel European smelting furnace of the national treasures and warrior group is used as the most advanced COREX in the world, and after being moved from Bao-steel to eight-steel, the eight-steel European smelting furnace is modified by a series of process technologies and has the technical characteristics of the self process, and the COREX furnace is named as the European smelting furnace.
Eight steel European smelting furnaces are combined with Xinjiang fuel resources, full coke smelting is carried out in the initial stage of furnace opening, and reduction gas is insufficient according to the fuel structure of the full coke, so that stable production of the European smelting furnaces cannot be realized. Therefore, the production of the European smelting furnace has the following defects: 1. the insufficient gas amount causes the metallization rate of the shaft furnace to be only 25 percent. The COREX furnace can reach 60%. 2. The coke ratio cannot be further reduced due to the limitation of the metallization rate of the shaft furnace. 3. The silicon content of molten iron is higher, the average silicon content of molten iron in an European and metallurgical furnace since the furnace is opened with larger production pressure for the production of the subsequent working procedures is 2.66 percent, the silicon content of the molten iron is higher than that of the molten iron in a blast furnace or a COREX furnace, and the analysis of the high silicon content of the molten iron is as follows: the fuel ratio is nearly 1 time higher than the furnace; blowing pure oxygen at the tuyere; the t-stage is about 1.7 times higher than the blast furnace.
Disclosure of Invention
The invention aims to solve a series of problems of insufficient gas quantity, high fuel ratio, high coke ratio and high silicon content of pig iron in an European smelting furnace, and the invention aims to provide a method for injecting coal in the European smelting furnace, which can improve the quality of reduced coal gas of the European smelting furnace, achieve the CO2 content of the reduced gas of the European smelting furnace of less than 9 percent, replace part of low-strength coke, foam coal and semi-coke, further optimize the fuel structure of the European smelting furnace, reduce the fuel consumption, reduce the energy consumption of the European smelting furnace process, reduce the production cost, and further optimize the operation process of the European smelting furnace and be more flexible.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a method for injecting coal into a smelting furnace, comprising the following steps:
1) Mixing the soft coal with the volatile content of more than 35% and the semi-coke with low volatile content according to the mass ratio of 3:1 by adopting a soft coal injection process, so that the volatile content of the mixed fuel is slightly less than 25%, crushing and screening the mixed fuel into crushed coal, and loading the crushed coal into a raw coal bin;
2) Grinding crushed coal to minus 200 meshes with a coal mill to obtain coal powder accounting for more than 60%; drying the pulverized coal by adopting flue gas generated by a flue gas furnace to enable the moisture of the pulverized coal to be less than 2%; the temperature of the dry flue gas at the inlet of the coal mill is 210-250 ℃, the temperature of the flue gas is kept above the dew point temperature, and the sealing air of the coal mill is replaced by nitrogen, so that the oxygen content of a coal grinding and pulverizing system is less than 12%, and the CO content is less than 300ppm;
3) The flue gas in the step 2) enters a coal mill by virtue of the suction force of a smoke exhaust fan to convey pulverized coal to a cloth bag box body, and the cloth bag box body is subjected to gas-powder separation to load the finished pulverized coal into a pulverized coal bin;
4) The method comprises the steps of sequentially filling coal powder into 3 injection tanks at the lower part of a cloth bag box body, wherein the injection tanks comprise coal feeding and discharging devices, pressurizing, depressurizing and fluidizing devices, the coal is fed uniformly and stably through pressurizing and fluidizing, the coal is fed again after depressurizing, cyclic operation is carried out, the pressurizing and fluidizing pressure is 1.2-1.6 MPa, the coal powder is conveyed to a European smelting furnace tower by nitrogen gas, the method adopts dense-phase pneumatic conveying, the gas pressure is more than or equal to 0.6 MPa+ in the European smelting furnace gasification furnace and the pressure loss of 0.1 MPa+0.1 MPa+ through conveying pipelines and equipment, the injection tanks are connected with a nitrogen gas source, 3 groups of injection tanks are used as injection tanks for the coal powder, and the bottom valve is used for mutually switching any one of two paths of coal feeding main pipes to inject the coal powder into a vault and an oxygen tuyere of the European smelting furnace gasification furnace;
5) Setting a 15Nm higher than the calculated value according to the smelting rate 3 The unit consumption of the oxygen at the tuyere of the tHM, the diameter phi 30 of the tuyere, the factory pressure is set to be 0.35-0.37 Mpa, and the flow rate of the oxygen is 165-180 m/s;
6) Adjusting the distribution gear of the shaft furnace, adjusting the quantity and the oxygen quantity of oxygen burners, and controlling the cold gas CO 2 6-12%, and maintaining 50-65% DRI metallization rate;
7) Maintaining the total coke ratio to 15-18%, and adjusting and controlling the furnace temperature through the ratio of the foam coal to the coke foam;
8) Maintaining the fuel ratio of 1000-1020 kg/t, controlling the temperature of molten iron to be not lower than 1500℃ and [ Si ]]More than or equal to 0.6%, e.g. continuous 2 furnaces PT<Increasing the coke ratio by 2-3% at 1500 ℃, adjusting the coke ratio according to the change of the furnace temperature, controlling the alkalinity of slag to be 1.13-1.20, and controlling the Al 2 O 3 <15.2%,MgO >8%;
9) After coal injection, according to the change of the gasification furnace burden level, adjusting the rotation speed of the coal screw to keep the specified material level LIR6425 20 percent, if the material level is increased, reducing the rotation speed of the coal screw and the DRI screw by 5 percent, otherwise, properly improving the rotation speed of the coal screw and the DRI screw, and keeping the rotation speed ratio of the coal/DRI screw unchanged;
10 The DRI turning plate and the gear of the coal distributor are adjusted according to the requirement, and coal and coke are mainly distributed between the center and the material surface in principle so as to dredge the center and inhibit the edge airflow;
11 Increasing or decreasing the oxygen amount of the oxygen burner nozzle, and keeping the temperature of the vault at 1050-1100 ℃;
12 When the pressure difference of the tuyere oxygen and the gasification furnace is less than 100KPa and is higher than the required range, the pressure of the factory is increased to 0.38-0.4 Mpa, and the DRI edge gear is increased;
13 Smelting rate of initial coal injection control 130): after the coal injection conditions are met, 6 coal guns including No. 1, no. 5, no. 11, no. 15, no. 19 and No. 25 are firstly added for injecting coal, the coal injection quantity of a single coal gun is controlled to be about 1t/h, the coal injection ratio is about 50kg/t, and the coal injection quantity of 6t/h is maintained for 1 day; maintaining the smelting rate of 130t/h and the tuyere oxygen content of 51200Nm 3 Per hour and per air inlet oxygen consumption 440Nm 3 T is unchanged; the pressure of the factory is set to be 0.25-0.3 Mpa; maintaining a DRI metallization rate of greater than 60%; the pellet ratio of the shaft furnace is kept to be 50-65%, the lump ore ratio is 35-50%, the coke ratio is 11%, the ash content of coal and coke is controlled to be about 300kg/t, the slag alkalinity is controlled to be 1.10-1.15, and the Al2O3 is controlled<13%,MgO >8%; maintaining 950kg/t fuel ratio, controlling molten iron temperature at 1500-1520 deg.c and Si]More than or equal to 0.8 percent; the shaft furnace material distribution control comprises gear adjustment, wherein the gear adjustment comprises that 1.2 meters of gear, the material distribution angle is 21.5, the relative thickness is reduced from 0.4 to 0.1 from 0.1 to 0.6,2.8 meters of gear, and the material distribution time is adjusted from 260s to 240s; increasing the smelting rate of 130 to 135 to 140 to 150 to 165t/h gradually along with the increase of the coal injection ratio;
14 Operating at 165t/h smelting rate, setting total coal injection amount to 5t/h, tank pressure to 0.9MPa, and compensating air flow to 300Nm 3 And/h, controlling the pulverized coal quantity of each main pipe to be stabilized at 3t/h through a main pipe flow regulating valve, controlling the normal coal injection quantity to be 6-15 t/h, controlling the coal injection ratio to be 50-100 kg/t, and controlling the single-gun coal injection quantity to be 0.4-0.7 t/h; according to the smelting rateThe fixed ratio is 15Nm higher than the calculated value 3 The unit oxygen consumption of the tuyere with the tHM of about, the diameter phi 30 of the tuyere, the factory pressure of 0.30-0.32 Mpa and the oxygen flow rate of 185-195 m/s; adjusting the distribution gear of the shaft furnace, adjusting the quantity and the oxygen quantity of oxygen burners, controlling the cold gas CO2 6-9%, and keeping the DRI metallization rate at 50-65%; maintaining the coke ratio of the shaft furnace to the gasifier to be 5-8%, and the total coke ratio to be 15-18%, adjusting 7kg foam coal ratio to be a regulating principle by reducing the silicon content (Si) of pig iron at the furnace temperature by 0.1%, and adjusting 5kg coke ratio by considering the silicon content (Si) of iron by 0.1% when the gasification furnace working condition, tuyere breakage, furnace temperature and the like do not have variation trend during coal injection for a period of time;
15 Maintaining the fuel ratio of 850-900 kg/t, controlling the temperature of molten iron to be not lower than 1500 ℃, controlling [ Si ] to be more than or equal to 0.6 percent, if the PT of a continuous 2 furnace is less than 1500 ℃, increasing the coke ratio by 2-3 percent, adjusting the coke ratio according to the change of the furnace temperature, controlling the alkalinity of slag to be 1.13-1.20, controlling the Al2O3 to be less than 15.2 percent and controlling the MgO to be more than 8 percent;
16 After coal injection, adjusting the spiral speed of coal according to the change of the gasification furnace burden level to keep the specified material level: the gasification furnace is provided with 5 groups of nuclear source material level indicators LIR-04621, LIR-04622, LIR-04623, LIR-04624 and LIR-04625 from low to high, wherein the material level of the gasification furnace is required to be controlled to be 20 percent by LIR 6425; if the material level is increased, the rotation speed of the coal screw and the DRI screw is reduced by 5 percent, otherwise, the rotation speed of the coal screw and the DRI screw is properly increased, and the rotation speed ratio of the coal/DRI screw is kept unchanged;
17 The DRI turning plate and the gear of the coal distributor are adjusted according to the requirement, and the pulverized coal and coke are distributed between the center and the material surface so as to dredge the center and inhibit the edge airflow;
18 Increasing or decreasing the oxygen amount of the oxygen burner nozzle, and keeping the temperature of the vault at 1050-1100 ℃;
19 When the pressure of the oxygen at the tuyere and the pressure difference of the gasification furnace are lower than 100KPa and are higher than the required range, the pressure of the factory is increased to 0.38-0.4 Mpa, and the DRI edge gear is increased.
After pulverized coal is injected into the European smelting furnace by adopting the method, the gas composition is improved, and the operation effects of the European smelting furnace gasification furnace and the shaft furnace condition are as follows:
1. the coal injection can effectively improve the effective reducing gas components in the reducing gas, the CO2 is reduced to 9% from 15% of the non-coal injection after the reducing gas is improved, the metallization rate of the shaft furnace is increased to 59.6% from 19.8% before the coal injection, and the gas utilization rate of the shaft furnace is increased to 29.7% from 20% before the coal injection.
2. After the quality of the gas of the shaft furnace is improved, the amount of top gas required by the shaft furnace is reduced, so that the unit consumption of the top gas is reduced.
3. The metallization rate of the shaft furnace is increased to effectively reduce the fuel ratio of the gasification furnace, greatly reduce the coke ratio of the gasification furnace, reduce the coke ratio of the gasification furnace from 450kg/tHm to 150kg/tHm, reduce the silicon content of pig iron from 1.83% to below 0.5% before coal injection, and fully heat the molten iron physically.
4. The metallization rate is increased by the coal injection of the European smelting furnace, the coke ratio and the fuel ratio are reduced, and the total oxygen unit consumption is reduced due to the reduction of the fuel consumption.
5. The injected pulverized coal generates a certain amount of H2 in the tuyere zone, H2 has stronger reduction activity than CO in the high-temperature environment of the tuyere zone, and the H2 is utilized to react with the sponge iron sufficiently to reduce the consumption of coke and foam coal. In addition, the heat consumption of the vault can be reduced by injecting the pulverized coal, so that the CH4 content in the generated coal gas is reduced, and the effect of reducing the coal consumption is also played to a certain extent.
After the pulverized coal is prepared by pulverizing and blowing, the pulverized coal is conveyed to a tuyere and a vault of a gasification furnace through a pipeline to spray the pulverized coal, nitrogen is taken as a conveying carrier of the pulverized coal, the pulverized coal is sprayed from the tuyere and the vault, the pulverized coal is cracked to generate H2, C and oxygen are subjected to chemical reaction to generate reducing gas CO, tuyere gas is formed to replace the reducing gas generated by coke combustion, and heat required by the tuyere is provided.
The coal gas generated by the tuyere and the vault is mixed in the vault of the gasifier and then enters the shaft furnace to reduce the ore in the shaft furnace, so that the metallization rate of the ore reaches 59.6%. The reduced DRI sponge iron with high metallization rate is input into a gasification furnace and is subjected to gas reheating reduction to form primary slag iron.
The coal injection of the European smelting furnace is not only a technology of replacing coke with powder and directly utilizing pulverized coal, but also a comprehensive new technology for optimizing the smelting reduction process of the European smelting furnace. The coke and foam coal consumption is directly reduced in the same ratio after coal injection, and meanwhile, the theoretical combustion temperature before the tuyere can be reduced by coal injection, so that the silicon content of molten iron is reduced; the lower regulating means can be added to stabilize the daily furnace temperature; increasing the gas quantity of the hearth and reducing components in the gas, and promoting the reduction process; by combining with the distribution of the gasification furnace, the utilization of the heat energy and chemical energy of the gas in the furnace is improved, and the total fuel consumption is reduced. Meanwhile, as the pulverized coal before the tuyere is conveyed into N2 to reduce the temperature of the front end of the tuyere, the reflux ablation of high-temperature coal gas on the tuyere is obviously reduced under the condition that the pulverized coal is fully combusted, the breakage rate of the tuyere is reduced, the temporary damping down rate is reduced, and the production operation rate is improved.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a diagram of a process plant according to the present invention.
Detailed Description
A method for spraying coal in a European smelting furnace, as shown in figures 1 and 2, comprises the following steps:
1) Mixing the soft coal with the volatile content of more than 35% and the semi-coke with low volatile content according to the mass ratio of 3:1 by adopting a soft coal injection process, so that the volatile content of the mixed fuel is slightly less than 25%, crushing and screening the mixed fuel into crushed coal, and loading the crushed coal into a raw coal bin 1;
2) The crushed coal is supplied to a mill 3 through a coal feeder 2 and is ground into minus 200 meshes which account for more than 60 percent through the mill; at the moment, the coal dust is dried by adopting the flue gas generated by the flue gas furnace 4, so that the moisture of the raw coal is less than 2%; because the high-temperature smoke of 1500-1800 ℃ is generated by the smoke furnace, a part of discharged tail gas is led into the smoke furnace to be mixed with the smoke generated by the smoke furnace by utilizing a self-circulation adjusting method from the outlet of the smoke exhaust fan to the pipeline of the chimney 7, the temperature of the dry gas at the inlet of the coal mill is 210-250 ℃, the temperature of the smoke entering the mill is proper, and the temperature of the waste gas is kept above the dew point temperature. In addition, a certain amount of nitrogen is used for replacing sealing air of the coal mill, so that the oxygen content of a coal grinding and pulverizing system is less than 12%, and the CO content is less than 300ppm.
The flue gas furnace 4 is equipment for generating high-temperature gas by burning the gas of the European and Metallurgical furnace and mixing the gas with self-circulation tail gas of the pulverizing system. The gas stove 4 consists of a main burner, an ignition burner, an automatic ignition device, a flame monitor, a stove body and a control facility. The furnace body is internally provided with a combustion chamber and a mixing chamber. The self-circulation tail gas of the pulverizing system enters the mixing chamber from the tangential direction and is fully mixed with the high-temperature smoke. The burner is arranged in front of the gas furnace 4, and the igniter burns coke oven gas; the main burner burns the ouye furnace gas. The load of the gas furnace 4 is automatically adjusted according to the set value of the outlet temperature of the coal mill.
After entering the mill, the dry flue gas carries the pulverized coal with certain fineness to a separator positioned at the upper part of the coal mill for separation. The coarse coal powder which is not satisfactory falls back onto the grinding disc and is ground again. The pulverized coal with qualified fineness enters the cloth bag box body along with the drying gas through the rising powder feeding pipe. The coal gangue which cannot be finely ground falls into a coal gangue collecting device at the lower part of the coal mill and is periodically removed by manpower.
3) The dry flue gas in the step 2) forms negative pressure by the suction force of the smoke exhaust fan, and the negative pressure is gradually increased from the outlet of the dry flue gas furnace 4 to the inlet of the smoke exhaust fan through the cloth bag box body. The dry gas in the flue gas furnace enters a mill to convey coal powder to a cloth bag box body 5 through the work of a flue gas fan, and finished coal powder is loaded into a coal powder bin after gas-powder separation in the cloth bag box body; the bag box body is an external filter type bag low-pressure pulse bag powder collector. The gas containing coal dust enters from a turbid air chamber at the lower part of one side of the box body, the coal dust stays outside the bag through the outer filter type cloth bag, and the coal dust is deposited to the lower part of the cloth bag box body through gravity. The dry flue gas entering the bag passes through the cloth bag and the framework of the cloth bag, and is discharged from the upper bag opening to the air purifying chamber of the box body. The filter bags are arranged in a plurality of rows, each row is provided with a pulse valve and a blowing pipe, the nozzles on the pipes are aligned to the center of the filter bags, and the fixed pressure difference is adopted to carry out back blowing to clean the coal dust attached to the upper parts of the filter bags so as to ensure the air permeability of the filter bags.
4) The coal powder is collected by the cloth bag box body and enters the vibrating screen 8, and the invention adopts the closed vibrating screen which has the function of removing the key equipment of sundries in the coal powder collected by the powder collecting device, and can continuously and effectively remove the sundries in the removed coal powder. Light impurities such as plastic skin are removed, and clean coal powder enters a coal powder bin 10 through a coal dropping pipe 9. The top of the pulverized coal bin 10 is provided with a moisture absorption pipe 11 connected to the cloth bag box body, which is used for removing the moisture of the gas in the pulverized coal bin and keeping the moisture of the pulverized coal within a certain range.
The coal powder is sequentially filled into 3 blowing tanks 12 at the lower part of the cloth bag box body, a pressure release and diffusion pipe 13 at the upper part of the blowing tanks is led to the cloth bag box body, and the coal powder falls into the blowing tanks by gravity. The blowing tank 12 comprises a coal inlet device, a coal outlet device, a pressurizing device, a pressure relief device and a fluidizing device, wherein the coal inlet device is used for fluidizing the coal through pressurization after coal inlet, so that the coal outlet is uniform and stable, the coal inlet device is used for feeding the coal after pressure relief, and the circulating operation is performed. The pressure of the pressurized fluidization is 1.2-1.6 MPa, and the pulverized coal is conveyed to a tower of the European smelting furnace by nitrogen gas through pressurized fluidization and air supplementing. The invention adopts dense phase pneumatic conveying, the gas pressure is more than or equal to the pressure (0.6 MPa) in the gasification furnace of the European smelting furnace and the pressure loss of 0.1 MPa+0.1 MPa of the pressure loss passing through a conveying pipeline and equipment. The blowing tank 12 is connected with a nitrogen gas source, 3 groups of blowing tanks are used as blowing tanks for pulverized coal, and any one of the two paths of coal conveying main pipes 14 and 15 can be mutually switched through a bottom valve to convey and blow the pulverized coal to the dense phase of the European smelting furnace.
5) The method of the invention comprises the steps of injecting pulverized coal from the vault of the gasification furnace of the European smelting furnace and the oxygen tuyere;
the coal conveying main pipes 14 and 15 are erected to a European smelting furnace tower, and distributors 16, 17 and 18 are arranged at proper positions of the tower, wherein the coal conveying main pipe 14 is connected with the distributor 16, and the coal conveying main pipe 15 is respectively connected with the distributor 17 and the distributor 18.
The dome oxygen coal guns 19 are 4 in total. The distributor 16 is connected with an oxygen coal gun 19 (4 groups in total) for injecting pulverized coal into the vault through 4 groups of coal conveying pipelines. The pulverized coal can be started and stopped to be injected into the dome oxygen coal gun 19 by opening and closing the valve according to production requirements.
The distributor 17 is connected to an oxygen coal gun 20 (14 groups in total) for injecting pulverized coal into the air openings through 14 groups of coal conveying pipelines and 14 oxygen air openings (odd-numbered air openings) for injecting pulverized coal into the odd-numbered air openings. The distributor 18 is connected to an oxygen-coal gun 20 (14 groups in total) for injecting pulverized coal into the air openings through 14 groups of coal conveying pipelines and 14 oxygen air openings (even-numbered air openings) for injecting pulverized coal into the even-numbered air openings. The tuyere oxygen coal guns 20 are 28 groups. The pulverized coal can be started and stopped to be injected into the tuyere oxygen coal gun 20 by opening and closing the valve according to production requirements.
6) Operating at a smelting rate of 150t/h, and fully feeding 2 coal injection main pipes, 2 distributors and 28 coal guns into coal injection. Starting a flow regulating valve and a flow meter of 2 main pipes, setting the total initial coal injection amount to 5t/h, the tank pressure to 0.9MPa, and setting the air supplementing flow to 300Nm 3 And/h. The pulverized coal quantity of each main pipe is controlled to be stabilized at about 3t/h through the main pipe flow regulating valve. The normal coal injection amount is controlled to be 6-15 t/h, and the coal injection ratio is controlled to be 50-100 kg/t. The coal injection amount of a single gun is controlled to be 0.4-0.7 t/h.
7) Setting 15Nm higher than calculated value according to smelting rate 3 Tuyeres oxygen unit consumption around/tHM. The diameter phi 30 (part phi 31) of the tuyere, the pressure of the factory is set to be 0.35-0.37 Mpa, and the flow rate of oxygen is 165-180 m/s;
8) Adjusting the distribution gear of the shaft furnace, adjusting the quantity and the oxygen quantity of oxygen burners, controlling the cold gas CO2 6-12%, and keeping the DRI metallization rate at 50-65%.
9) The coke ratio of the shaft furnace to the gasification furnace is kept to be 5-8%, and the total coke ratio is kept to be 15-18%. In principle, the coke ratio is kept unchanged, and the furnace temperature is regulated and controlled through the ratio of the pulverized coal to the coke powder. When the gasification furnace has no variation trend in working condition, breakage of the tuyere, furnace temperature and the like in coal injection for a period of time, proper reduction of the coke ratio is considered.
10 The fuel ratio of 1000-1020 kg/t is maintained, the temperature of molten iron is controlled to be not lower than 1500 ℃, and [ Si ] is not less than 0.6%. If PT of the continuous 2 furnaces is less than 1500 ℃, the coke ratio is increased by 2-3%, and the coke ratio is adjusted according to the change of furnace temperature. The alkalinity of the slag is controlled to be 1.13-1.20, (Al 2O 3) <15.2 percent, (MgO) >8 percent.
11 After coal injection, the spiral speed of the coal is adjusted according to the change of the gasification furnace burden level, so that the specified material level (LIR 6425 20%) is maintained. If the material level is increased, the rotation speed of the coal screw and the DRI screw is reduced by 5 percent, otherwise, the rotation speed of the coal screw and the DRI screw is properly increased, and the rotation speed ratio of the coal/DRI screw is kept unchanged.
12 The DRI turning plate and the gear of the coal distributor are adjusted according to the requirement, and in principle, coal and coke are distributed between the center and the material surface to dredge the center and inhibit the edge airflow.
13 By increasing or decreasing the oxygen amount of the oxygen burner, the temperature of the vault is maintained at 1050-1100 ℃.
14 When the pressure of the oxygen at the tuyere and the pressure difference of the gasification furnace (< 100 KPa) are higher than the required range, the pressure of the factory can be increased to 0.38-0.4 Mpa, and the DRI edge gear can be increased.
Smelting rate of initial coal injection control 130: after the coal injection conditions are met, 6 coal guns are added for injecting coal, namely 1#, 5#, 11#, 15#, 19#, 25# in total. The coal injection amount of a single gun is controlled to be about 1t/h, and the coal injection ratio is about 50kg/t. The coal injection amount at 6t/h is maintained for 1 day. The smelting rate of 130t/h, the tuyere oxygen amount of 51200Nm3/h and the tuyere oxygen unit consumption of 440Nm3/t are kept unchanged. The pressure of the factory is set to be 0.25-0.3 Mpa; the DRI metallization rate of above 60% is maintained. The pellet ratio of the shaft furnace is kept to be 50-65%, the lump ore ratio is kept to be 35-50% and the coke ratio is kept to be 11%. The ash content of coal and coke is controlled, and the slag ratio is controlled to be about 300 kg/t. The basicity of the slag is controlled to be 1.10-1.15, (Al 2O 3) <13 percent and (MgO) >8 percent. Maintaining the fuel ratio of 950kg/t, controlling the temperature of molten iron at 1500-1520 ℃, and controlling the [ Si ] to be more than or equal to 0.8 percent. And (3) material distribution control of the shaft furnace: gear adjustment, namely 1.2 m gear, the relative thickness is increased from 0.1 to 0.6,2.8 m gear, the relative thickness is reduced from 0.4 to 0.1, and the cloth time is adjusted from 260s to 240s.
After coal injection, the smelting period may be prolonged by 1-2 h, the rotation speed of coal screw and DRI screw should be controlled, and the material level of the gasification furnace is tracked. The gear of the existing DRI turning plate and coal distributor is unchanged, and the aim of dredging the center and inhibiting the edge airflow is basically achieved. With the increase of the coal injection ratio, the change of the pressure difference of the gasification furnace can be seen, the coke ratio of the gasification furnace is properly increased, and the air permeability and the hearth activity are improved. When the coal injection amount is increased, the coal gun is increased by 2 branches each time and the coal injection amount is symmetrical in the circumferential direction, and the coal injection amount is increased by 2t/h each time. And after adjustment, the adjustment is kept unchanged for at least 4 hours, and the adjustment action is considered according to the change of the furnace condition parameters. After the coal injection amount is increased, if the molten iron temperature of a continuous 2-furnace is >1530 ℃ and [ Si ] >1.0%, the addition amount of foam coal can be reduced, and the coal is reduced according to the same amount as the coal injection ratio, and at the moment, the control of the fuel ratio is based on the principle that PT is >1500 ℃ and stable. After the coal injection amount is increased and the addition amount of the furnace top lump coal is reduced, if the temperature of the furnace top of the gasifier is increased by more than 1080 ℃, the number of oxygen burners or the oxygen amount can be properly reduced, and DT <1100 ℃ is controlled.
Increasing the smelting rate of 130 to 135 to 140 to 150 to 165t/h gradually along with the increase of the coal injection ratio; operating at 165t/h smelting rate, setting total coal injection amount to 5t/h, tank pressure to 0.9MPa, and compensating air flow to 300Nm 3 And/h, controlling the pulverized coal quantity of each main pipe to be stabilized at 3t/h through a main pipe flow regulating valve, controlling the normal coal injection quantity to be 6-15 t/h, controlling the coal injection ratio to be 50-100 kg/t, and controlling the single-gun coal injection quantity to be 0.4-0.7 t/h; setting 15Nm higher than calculated value according to smelting rate 3 The unit oxygen consumption of the tuyere with the tHM of about, the diameter phi 30 of the tuyere, the factory pressure of 0.30-0.32 Mpa and the oxygen flow rate of 185-195 m/s; adjusting the distribution gear of the shaft furnace, adjusting the quantity and the oxygen quantity of oxygen burners, controlling the cold gas CO2 6-9%, and keeping the DRI metallization rate at 50-65%; keeping the coke ratio of the shaft furnace to the gasification furnace to 5-8%, keeping the total coke ratio to 15-18%, keeping the coke ratio unchanged in principle, and adjusting and controlling the furnace temperature through the foam coal proportion; according to the principle that 7kg of foam coal ratio is adjusted every 0.1% of the silicon content [ Si ] in the pig iron at the furnace temperature is reduced, when the gasification furnace working condition, the tuyere breakage, the furnace temperature and the like do not have variation trend in coal injection for a period of time, 5kg of coke ratio is adjusted every 0.1% of the silicon content [ Si ] in the iron is considered. Keeping the fuel ratio of 850-900 kg/t, controlling the temperature of molten iron to be not lower than 1500℃ and [ Si ]]More than or equal to 0.6%, e.g. continuous 2 furnaces PT<Increasing the coke ratio by 2-3% at 1500 ℃, adjusting the coke ratio according to the change of the furnace temperature, controlling the alkalinity of slag to be 1.13-1.20, and controlling the alkalinity of Al2O3<15.2%,MgO>8%;
After coal injection, the spiral speed of the coal is adjusted according to the change of the gasification furnace burden level, so that the specified material level is maintained: the gasification furnace is provided with 5 groups of nuclear source material level indicators LIR-04621, LIR-04622, LIR-04623, LIR-04624 and LIR-04625 from low to high, wherein the material level of the gasification furnace is required to be controlled to be 20 percent by LIR 6425; if the material level is increased, the rotation speed of the coal screw and the DRI screw is reduced by 5 percent, otherwise, the rotation speed of the coal screw and the DRI screw is properly increased, and the rotation speed ratio of the coal/DRI screw is kept unchanged;
the DRI turning plate and the gear of the coal distributor are adjusted according to the requirement, and the pulverized coal and coke are distributed between the center and the material surface so as to dredge the center and inhibit the edge airflow;
the temperature of the vault is kept at 1050-1100 ℃ by increasing or decreasing the oxygen amount of the oxygen burner;
when the pressure of the oxygen at the tuyere and the pressure difference of the gasification furnace are less than 100KPa and are higher than the required range, the pressure of the factory is increased to 0.38-0.4 Mpa, and the DRI edge gear is increased.
In summary, the method of the invention sprays coal powder to the vault area of the gasifier and the tuyere area of the gasifier respectively, and has the dual functions of both the vault area of the gasifier and the oxygen tuyere and spraying coal powder, and the specific flow chart is shown in the flow chart 1. As shown in figure 2, raw coal suitable for manufacturing reducing gas by using a European smelting furnace and a melt gasification furnace is crushed, screened and transported to generate crushed coal, and in order to facilitate the generation of more coal gas, the invention adopts a bituminous coal injection process, is mixed with semi-coke, is filled into a raw coal bin 1, and is supplied to a mill 3 through a coal feeder 2. The pipeline from the outlet of the smoke exhaust fan to the chimney 7 is connected with a self-circulation pipeline, enters the smoke furnace 4 and is mixed with the smoke generated by the self-circulation pipeline, and the generated smoke is used for drying coal dust. The dry flue gas forms negative pressure by means of the suction force of a smoke exhaust fan 6, the negative pressure is gradually increased from a dry flue gas furnace 4, a grinder 3 and a cloth bag box 5 to an inlet of the smoke exhaust fan, dry flue gas in the flue gas furnace 4 enters the grinder 3 to convey pulverized coal to the cloth bag box 5 through the work of the smoke exhaust fan 6, the pulverized coal is separated in the cloth bag box 5 through gas-powder separation, the pulverized coal is collected through the cloth bag box 5, enters a vibrating screen 8, and enters a pulverized coal bin 10 through a coal dropping pipe 9. The top of the pulverized coal bin 10 is provided with a moisture absorption pipe 11 connected to the cloth bag box 5. The coal powder is sequentially filled into 3 blowing tanks 12 at the lower part of the cloth bag box body 5, a pressure relief and diffusion pipe 13 at the upper part of the blowing tanks 12 is led to the cloth bag box body 5, and the coal powder falls into the blowing tanks 12 by gravity. The blowing tank 12 conveys and blows coal dust to the dense phase of the European smelting furnace through the bottom valve to the two paths of coal conveying main pipes 14 and 15. The coal conveying main pipes 14 and 15 are erected to a European smelting furnace tower, and distributors 16, 17 and 18 are arranged at proper positions of the tower, wherein the coal conveying main pipe 14 is connected with the distributor 16, and the coal conveying main pipe 15 is respectively connected with the distributor 17 and the distributor 18. The distributor 16 is connected with an oxygen coal gun 19 (4 groups in total) for injecting pulverized coal into the vault through 4 groups of coal conveying pipelines. The distributor 17 is connected to an oxygen coal gun 20 (14 groups in total) for injecting pulverized coal into the air openings through 14 groups of coal conveying pipelines and 14 oxygen air openings (odd-numbered air openings) for injecting pulverized coal into the odd-numbered air openings. The distributor 18 is connected to an oxygen-coal gun 20 (14 groups in total) for injecting pulverized coal into the air openings through 14 groups of coal conveying pipelines and 14 oxygen air openings (even-numbered air openings) for injecting pulverized coal into the even-numbered air openings.
Example 1: full coke smelting period (reference operating period)
In this example (oxygen tuyere coal injection is 0kg/t iron):
the main operation indexes of smelting 1t molten iron under the operating condition of full coke smelting in the European smelting furnace are shown in the following table. The smelting rate is 130, the pig iron yield is 3120t, the coke ratio (large coke+small coke) is 650kg/t, the tuyere coal ratio is 0kg/t, the vault coal ratio is 0kg/t, the foam coal+coke foam is 0kg/t, the fuel ratio is 650kg/t, and the metallization rate is 19.8%.
The following table shows the main technical economic index of the smelting of 1t molten iron in a hydrometallurgy furnace under the operating condition of full coke operation (reference operating period), in this embodiment (coal injection at an oxygen tuyere is 0kg/t iron):
example 2: (tuyere coal to 0kg/t iron, vault coal to 0kg/t iron)
In this embodiment:
the main operation indexes of smelting 1t molten iron under the operating condition of full coke smelting in the European smelting furnace are shown in the following table. The smelting rate is 135, the pig iron yield is 3240t, the coke ratio (large coke and small coke) is 500kg/t, the tuyere coal ratio is 0kg/t, the vault coal ratio is 0kg/t, the foam coal and coke foam are 400kg/t, the fuel ratio is 900kg/t, and the metallization rate is 22.3%.
In the following table, foam adding coal and coke adding operation is carried out, in the embodiment (the coal injection of the oxygen tuyere is 0kg/t iron), although the fuel structure is changed, the improvement of indexes such as metallization rate, pig iron [ Si ] and the like is not greatly influenced, only the cost reduction is influenced, and the main technical and economic indexes of smelting 1t molten iron in the European smelting furnace under the operation condition are as follows:
example 3: (tuyere coal ratio 30kg/t iron, vault coal ratio 50kg/t iron)
In this embodiment:
the main operation indexes of smelting 1t molten iron under the operating condition of full coke smelting in the European smelting furnace are shown in the following table. The smelting rate is 135, the pig iron yield is 3360t, the coke ratio (large coke and small coke) is 450kg/t, the tuyere coal ratio is 30kg/t, the vault coal ratio is 50kg/t, the foam coal and coke foam are 400kg/t, the fuel ratio is 880kg/t and the metallization rate is 32.9%.
The following table is matched with the operation of adding foam coal and coke foam, in the embodiment, the injection of the oxygen tuyere and the vault coal injection is 80kg/t iron, the gas making amount is improved, the fuel structure is changed, the influence on indexes such as metallization rate, pig iron [ Si ] and the like is obvious, meanwhile, the influence on the cost is large, and the main technical and economic indexes of smelting 1t molten iron in an European smelting furnace under the operation condition are that:
example 4: (tuyere coal ratio 60kg/t iron, vault coal ratio 100kg/t iron)
In this embodiment:
the main operation indexes of smelting 1t molten iron under the operating condition of full coke smelting in the European smelting furnace are shown in the following table. The smelting rate is 150, the pig iron yield is 3600t, the coke ratio (large coke and small coke) is 360kg/t, the tuyere coal ratio is 60kg/t, the vault coal ratio is 100kg/t, the foam coal and coke foam are 360kg/t, the fuel ratio is 880kg/t, and the metallization rate is 45.3%.
The following table is matched with the operation of adding foam coal and coke foam, in the embodiment, the injection of the oxygen tuyere and the vault coal injection is 160kg/t iron, the gas making amount is improved, the fuel structure is changed, the influence on indexes such as metallization rate, pig iron [ Si ] and the like is obvious, meanwhile, the influence on the cost is large, and the main technical and economic indexes of smelting 1t molten iron in an European smelting furnace under the operation condition are that:
example 5: (tuyere coal ratio 100kg/t iron, vault coal ratio 150kg/t iron)
In this embodiment:
the main operation indexes of smelting 1t molten iron under the operating condition of full coke smelting in the European smelting furnace are shown in the following table. The smelting rate is 165, the pig iron yield is 3960t, the coke ratio (large coke and small coke) is 250kg/t, the tuyere coal ratio is 100kg/t, the vault coal ratio is 150kg/t, the foam coal and coke foam are 200kg/t, the fuel ratio is 700kg/t, and the metallization rate is 59.6%.
The following table is matched with the operation of adding foam coal and coke foam, in the embodiment, the injection of the oxygen tuyere and the vault coal injection is 160kg/t iron, the gas making amount is improved, the fuel structure is changed, the influence on indexes such as metallization rate, pig iron [ Si ] and the like is obvious, meanwhile, the influence on the cost is large, and the main technical and economic indexes of smelting 1t molten iron in an European smelting furnace under the operation condition are that:
the European smelting furnace uses the tuyere and vault to spray coal powder as an operation means, 80-250 kg/t of dry coal powder is sprayed to produce gas, and the coal injection is not only a technology of replacing coke with powder and directly utilizing the coal powder, but also the smelting reduction process of the European smelting furnace is more optimized. With the increase of the coal injection amount, the on-site utilization amount of the carbon-containing dust-removing pulverized coal is continuously increased, the coke consumption is reduced, and the purchasing cost is reduced. The coal injection can reduce the theoretical combustion temperature before the tuyere, reduce the tuyere damage and reduce the content of molten iron [ Si ]; after coal injection, an air port and vault regulating means of the European smelting furnace can be added, so that the daily furnace temperature is stabilized, and the coke ratio and the fuel ratio rise caused by the fluctuation of the furnace temperature are reduced; after coal injection, the blast kinetic energy of the tuyere is increased, the distribution and heat exchange of the temperature field in the melting gasification furnace of the European smelting furnace are improved, the utilization of gas in the furnace is improved by combining with a material distribution technology, and the consumption of solid fuel is reduced. The smelting period of the gasification furnace is prolonged after coal injection, which is beneficial to solving the problem of insufficient furnace temperature during high smelting rate operation and improving the smelting rate. Therefore, the European smelting furnace coal injection technology can generate considerable indirect economic benefit if successfully applied.

Claims (1)

1. The method for spraying coal in the European smelting furnace is characterized by comprising the following steps:
1) Mixing the soft coal with the volatile content of more than 35% and the semi-coke with low volatile content according to the mass ratio of 3:1 by adopting a soft coal injection process, so that the volatile content of the mixed fuel is slightly less than 25%, crushing and screening the mixed fuel into crushed coal, and loading the crushed coal into a raw coal bin;
2) Grinding crushed coal to minus 200 meshes with a coal mill to obtain coal powder accounting for more than 60%; drying the pulverized coal by adopting flue gas generated by a flue gas furnace to enable the moisture of the pulverized coal to be less than 2%; the temperature of the dry flue gas at the inlet of the coal mill is 210-250 ℃, the temperature of the flue gas is kept above the dew point temperature, and the sealing air of the coal mill is replaced by nitrogen, so that the oxygen content of a coal grinding and pulverizing system is less than 12%, and the CO content is less than 300ppm;
3) The flue gas in the step 2) enters a coal mill by virtue of the suction force of a smoke exhaust fan to convey pulverized coal to a cloth bag box body, and the cloth bag box body is subjected to gas-powder separation to load the finished pulverized coal into a pulverized coal bin;
4) The method comprises the steps of sequentially filling coal powder into 3 injection tanks at the lower part of a cloth bag box body, wherein the injection tanks comprise coal feeding and discharging devices, pressurizing, depressurizing and fluidizing devices, the coal is uniformly and stably discharged through pressurization and fluidization, the coal is fed after depressurization, cyclic operation is carried out, the pressurized fluidization and air supplementing are carried out, the pressurized fluidization pressure is 1.2-1.6 MPa, the coal powder is conveyed to a European smelting furnace tower by nitrogen gas, the method adopts dense-phase pneumatic conveying, the gas pressure is more than or equal to 0.6 MPa+ in the European smelting furnace gasification furnace and the pressure loss of 0.1 MPa+0.1 MPa through conveying pipelines and equipment, the injection tanks are connected with a nitrogen gas source, 3 groups of injection tanks are used as injection tanks for the coal powder, and the bottom valve is used for mutually switching any one of two paths of main coal conveying pipes to inject the coal powder into a vault and an oxygen tuyere of the European smelting furnace gasification furnace;
5) Setting a 15Nm higher than the calculated value according to the smelting rate 3 The unit consumption of oxygen at the tuyere of the tHM, the diameter phi of the tuyere is 30mm, the factory pressure is set to be 0.35-0.37 MPa, and the flow rate of oxygen is 165-180 m/s;
6) Adjusting the distribution gear of the shaft furnace, adjusting the quantity and the oxygen quantity of oxygen burners, and controlling the cold gas CO 2 6~12%, maintaining 50-65% DRI metallization rate;
7) Maintaining the total coke ratio to 15-18%, and adjusting and controlling the furnace temperature through the ratio of the foam coal to the coke foam;
8) Maintaining the fuel ratio of 1000-1020 kg/t, controlling the temperature of molten iron to be not lower than 1500℃ and [ Si ]]More than or equal to 0.6%, e.g. continuous 2 furnaces PT<Increasing the coke ratio by 2-3% at 1500 ℃, adjusting the coke ratio according to the change of the furnace temperature, controlling the slag alkalinity R to be 1.13-1.20, and controlling the Al 2 O 3 <15.2%,MgO >8%;
9) After coal injection, according to the change of the gasification furnace burden level, adjusting the rotation speed of the coal screw to keep the specified material level LIR6425 20 percent, if the material level is increased, reducing the rotation speed of the coal screw and the DRI screw by 5 percent, otherwise, properly improving the rotation speed of the coal screw and the DRI screw, and keeping the rotation speed ratio of the coal/DRI screw unchanged;
10 The DRI turning plate and the gear of the coal distributor are adjusted according to the requirement, and coal and coke are mainly distributed between the center and the material surface in principle so as to dredge the center and inhibit the edge airflow;
11 Increasing or decreasing the oxygen amount of the oxygen burner nozzle, and keeping the temperature of the vault at 1050-1100 ℃;
12 When the pressure of the oxygen at the tuyere and the pressure difference of the gasification furnace are smaller than 100kPa and are higher than the required range, the pressure of the factory is increased to 0.38-0.4 MPa, and the DRI edge gear is increased;
13 Initial coal injection control 130t/h smelting rate): after the coal injection conditions are met, 6 coal guns are added for injecting coal, namely 1#, 5#, 11#, 15#, 19#, 25# and the coal injection quantity of a single coal gun is controlled to be 1t/h, the coal injection ratio is 50kg/t, and the coal injection quantity is maintained for 1 day; maintaining the smelting rate of 130t/h and the tuyere oxygen content of 51200Nm 3 Per hour and per air inlet oxygen consumption 440Nm 3 T is unchanged; the pressure of the factory is set to be 0.25-0.3 MPa; maintaining a DRI metallization rate of greater than 60%; the pellet ratio of the shaft furnace is kept to be 50-65%, the lump ore ratio is 35-50%, the coke ratio is 11%, the ash content of coal and coke is controlled to be 300kg/t, the slag ratio is controlled to be 1.10-1.15, the alkalinity of slag is controlled to be 1.10-1.15, and the Al is controlled to be 11% 2 O 3 <13%,MgO >8%; maintaining 950kg/t fuel ratio, controlling molten iron temperature at 1500-1520 deg.c and Si]More than or equal to 0.8 percent; shaft furnace material distribution control, gear adjustment, material distribution angle 21.5 degrees, relative thickness from 0.1 to 0.6,2.8 meters and gear adjustment0.4 is reduced to 0.1, and the distribution time is adjusted from 260s to 240s; increasing the smelting rate of 130 to 135 to 140 to 150 to 165t/h gradually along with the increase of the coal injection ratio;
14 Operating at 165t/h smelting rate, setting total coal injection amount to 5t/h, tank pressure to 0.9MPa, and compensating air flow to 300Nm 3 And/h, controlling the pulverized coal quantity of each main pipe to be stabilized at 3t/h through a main pipe flow regulating valve, controlling the normal coal injection quantity to be 6-15 t/h, controlling the coal injection ratio to be 50-100 kg/t, and controlling the single-gun coal injection quantity to be 0.4-0.7 t/h; setting 15Nm higher than calculated value according to smelting rate 3 The unit consumption of oxygen at the tuyeres of the tHM, the diameter phi of the tuyeres is 30mm, the factory pressure is set to be 0.30-0.32 MPa, and the flow rate of oxygen is 185-195 m/s; adjusting the distribution gear of the shaft furnace, adjusting the quantity and oxygen quantity of oxygen burners, and controlling cold gas CO 2 6-9%, and maintaining 50-65% DRI metallization rate; maintaining the coke ratio of the shaft furnace to the gasification furnace to 5-8% and the total coke ratio to 15-18%, and making pig iron contain silicon [ Si ] through furnace temperature]% reducing by 0.1% and adjusting 7kg of foam coal ratio as a regulating principle, and when the gasification furnace working condition, tuyere breakage and furnace temperature do not have variation trend in coal injection period, taking iron-containing silicon [ Si ] into consideration]% adjust 5kg coke ratio per 0.1% decrease;
15 Maintaining the fuel ratio of 850-900 kg/t, controlling the temperature of molten iron to be not lower than 1500℃, [ Si ]]More than or equal to 0.6%, e.g. continuous 2 furnaces PT<Increasing the coke ratio by 2-3% at 1500 ℃, adjusting the coke ratio according to the change of the furnace temperature, controlling the slag alkalinity R to be 1.13-1.20, and controlling the Al 2 O 3 <15.2%,MgO>8%;
16 After coal injection, adjusting the spiral speed of coal according to the change of the gasification furnace burden level to keep the specified material level: the gasification furnace is provided with 5 groups of nuclear source material level indicators LIR-04621, LIR-04622, LIR-04623, LIR-04624 and LIR-04625 from low to high, wherein the material level of the gasification furnace is required to be controlled to be 20 percent by LIR 6425; if the material level is increased, the rotation speed of the coal screw and the DRI screw is reduced by 5 percent, otherwise, the rotation speed of the coal screw and the DRI screw is properly increased, and the rotation speed ratio of the coal/DRI screw is kept unchanged;
17 The DRI turning plate and the gear of the coal distributor are adjusted according to the requirement, and the pulverized coal and coke are distributed between the center and the material surface so as to dredge the center and inhibit the edge airflow;
18 Increasing or decreasing the oxygen amount of the oxygen burner nozzle, and keeping the temperature of the vault at 1050-1100 ℃;
19 When the pressure of the oxygen at the tuyere and the pressure difference of the gasification furnace are smaller than 100kPa and are higher than the required range, the pressure of the factory is increased to 0.38-0.4 MPa, and the DRI edge gear is increased.
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